I’ll never forget the first time I heard the maniacal cackle of a helmeted hornbill. I was standing beneath a massive fruiting fig tree in the middle of the Brunei rainforest – not exactly the heart of Borneo, but it was certainly wild enough for me – and craning my neck to catch a glimpse of the gibbons in the canopy. The ripening fruit was a magnet for all manner of other wildlife too, from wild pigs, diminutive mouse deer and tufted jungle king butterflies on the forest floor to pig-tailed macaques, barbets and, yes, hornbills in the treetops.